RKIP phosphorylation and STAT3 activation is inhibited by oxaliplatin and camptothecin and are associated with poor prognosis in stage II colon cancer patients

Circulating RKIP and pRKIP in Early-Stage Lung Cancer: Results from a Pilot Study

Background: Lung cancer (LC) is the leading cause of cancer-related deaths. Although low-dose computed tomography (LD-CT) reduces mortality, its clinical use is limited by cost, radiation, and false positives. Therefore, there is an urgent need for non-invasive and cost-effective biomarkers. The Raf Kinase Inhibitor Protein (RKIP) plays a crucial role in cancer development and progression and may also contribute to regulating the tumor-immune system axis. This protein has recently been described in biological fluids. Therefore, we conducted a pilot case-control study to assess RKIP and phosphorylated RKIP (pRKIP) levels in the urine and blood of LC patients. Methods: A novel enzyme linked immunosorbent assay (ELISA) assay was used to measure RKIP and pRKIP levels in urine and blood samples of two cohorts of LC patients and healthy controls (HSs). Furthermore, the biomarkers levels were correlated with tumor characteristics. Results: Serum, but not urine, levels of RKIP were significantly elevated in LC patients, distinguishing them from low- and high-risk healthy subjects with 93% and 74% accuracy, respectively. The RKIP/pRKIP ratio (RpR score) showed an accuracy of 90% and 79% in distinguishing LC patients from HS and HR-HS, respectively. Additionally, the RpR score correlated better with dimension, stage, and lymph node involvement in the tumor group. Conclusions: The serum RKIP and pRKIP profile may be a promising novel biomarker for early-stage LC.

Cross-Talks between Raf Kinase Inhibitor Protein and Programmed Cell Death Ligand 1 Expressions in Cancer: Role in Immune Evasion and Therapeutic Implications

Innovations in cancer immunotherapy have resulted in the development of several novel immunotherapeutic strategies that can disrupt immunosuppression. One key advancement lies in immune checkpoint inhibitors (ICIs), which have shown significant clinical efficacy and increased survival rates in patients with various therapy-resistant cancers. This immune intervention consists of monoclonal antibodies directed against inhibitory receptors (e.g., PD-1) on cytotoxic CD8 T cells or against corresponding ligands (e.g., PD-L1/PD-L2) overexpressed on cancer cells and other cells in the tumor microenvironment (TME). However, not all cancer cells respond-there are still poor clinical responses, immune-related adverse effects, adaptive resistance, and vulnerability to ICIs in a subset of patients with cancer. This challenge showcases the heterogeneity of cancer, emphasizing the existence of additional immunoregulatory mechanisms in many patients. Therefore, it is essential to investigate PD-L1's interaction with other oncogenic genes and pathways to further advance targeted therapies and address resistance mechanisms. Accordingly, our aim was to investigate the mechanisms governing PD-L1 expression in tumor cells, given its correlation with immune evasion, to uncover novel mechanisms for decreasing PD-L1 expression and restoring anti-tumor immune responses. Numerous studies have demonstrated that the upregulation of Raf Kinase Inhibitor Protein (RKIP) in many cancers contributes to the suppression of key hyperactive pathways observed in malignant cells, alongside its broadening involvement in immune responses and the modulation of the TME. We, therefore, hypothesized that the role of PD-L1 in cancer immune surveillance may be inversely correlated with the low expression level of the tumor suppressor Raf Kinase Inhibitor Protein (RKIP) expression in cancer cells. This hypothesis was investigated and we found several signaling cross-talk pathways between the regulations of both RKIP and PD-L1 expressions. These pathways and regulatory factors include the MAPK and JAK/STAT pathways, GSK3β, cytokines IFN-γ and IL-1β, Sox2, and transcription factors YY1 and NFκB. The pathways that upregulated PD-L1 were inhibitory for RKIP expression and vice versa. Bioinformatic analyses in various human cancers demonstrated the inverse relationship between PD-L1 and RKIP expressions and their prognostic roles. Therefore, we suspect that the direct upregulation of RKIP and/or the use of targeted RKIP inducers in combination with ICIs could result in a more targeted anti-tumor immune response-addressing the therapeutic challenges related to PD-1/PD-L1 monotherapy alone.

Cross-Talks between RKIP and YY1 through a Multilevel Bioinformatics Pan-Cancer Analysis

Recent studies suggest that PEBP1 (also known as RKIP) and YY1, despite having distinct molecular functions, may interact and mutually influence each other's activity. They exhibit reciprocal control over each other's expression through regulatory loops, prompting the hypothesis that their interplay could be pivotal in cancer advancement and resistance to drugs. To delve into this interplay's functional characteristics, we conducted a comprehensive analysis using bioinformatics tools across a range of cancers. Our results confirm the association between elevated YY1 mRNA levels and varying survival outcomes in diverse tumors. Furthermore, we observed differing degrees of inhibitory or activating effects of these two genes in apoptosis, cell cycle, DNA damage, and other cancer pathways, along with correlations between their mRNA expression and immune infiltration. Additionally, YY1/PEBP1 expression and methylation displayed connections with genomic alterations across different cancer types. Notably, we uncovered links between the two genes and different indicators of immunosuppression, such as immune checkpoint blockade response and T-cell dysfunction/exclusion levels, across different patient groups. Overall, our findings underscore the significant role of the interplay between YY1 and PEBP1 in cancer progression, influencing genomic changes, tumor immunity, or the tumor microenvironment. Additionally, these two gene products appear to impact the sensitivity of anticancer drugs, opening new avenues for cancer therapy.

Oxaliplatin inhibits colorectal cancer progression by inhibiting CXCL11 secreted by cancer-associated fibroblasts and the CXCR3/PI3K/AKT pathway

PURPOSE

Colorectal cancer (CRC) is a malignant tumor. Oxaliplatin (OXA) can inhibit cancer-associated fibroblasts (CAFs)-induced cancer progression. This study sought to explore the mechanism of OXA in CAFs-induced CRC development.

METHODS

CRC cell lines (Caco-2, SW620), normal fibroblasts (NFs), and CAFs were treated with OXA. NFs and CAFs were cultured. CAFs were treated with/without OXA (0.4 mM), and the supernatant was extracted as the conditioned medium (CM) to culture CRC cells. Cell malignant episodes, E-cadherin and Vimentin levels, CXCL1, CXCL2, CXCL3, CXCL8, and CXCL11 mRNA levels, CXCL11 protein level, and extracellular release were assessed. CAFs were transfected with interfering RNA sh-CXCL11 to silence CXCL11 or transfected with CXCL11 overexpression plasmids and treated with OXA to explore the role of CXCL11 in OXA-mediated CRC cells through CAFs. CXCL11 receptor CXCR3 levels in CRC cells and the PI3K/AKT pathway changes were examined. The xenogeneic tumor was transplanted in nude mice. CXCL11 and CXCR3 levels in tumor tissues, tumor volume, shape, size, weight, and Ki67 positive expressions were assessed.

RESULTS

CRC cell growths and epithelial-mesenchymal transformation were stimulated after culture with CAFs-CM, while OXA averted these trends. CXCL11 mRNA level was elevated most significantly, and its protein and extracellular secretion levels were raised, while OXA diminished the levels. CXCL11 silencing weakened the effects of CAFs-CM on promoting CRC proliferation and malignant episodes and CXCL11 overexpression averted OXA property on inhibiting CAFs-promoted CRC cell growth. CXCR3 and PI3K and AKT1 phosphorylation levels were raised in the CAFs-CM group but diminished by OXA. CXCL11 overexpression in CAFs averted OXA property on inhibiting CAFs-activated CXCR3/PI3K/AKT in CRC cells. OXA also inhibited the progression of xenograft tumors by limiting CAFs-secreted CXCL11.

CONCLUSIONS

OXA repressed CRC progression by inhibiting CAFs-secreted CXCL11 and the CXCR3/PI3K/AKT pathway.

Understanding Mechanisms of RKIP Regulation to Improve the Development of New Diagnostic Tools

Simple Summary

Raf Kinase Inhibitor protein is a protein that governs multiple intracellular signalling involved primarily in the progression of tumours and the development of metastases. In this review, we discussed the main mechanisms that regulate the expression and activity of RKIP with the aim of identifying the link between the transcriptional, post-transcriptional and post-translational events in different tumour settings. We also tried to analyse the studies that have measured the levels of RKIP in biological fluids in order to highlight the possible advantages and potential of RKIP assessment to obtain an accurate diagnosis and prognosis of various tumours.

Abstract

One of the most dangerous aspects of cancer cell biology is their ability to grow, spread and form metastases in the main vital organs. The identification of dysregulated markers that drive intracellular signalling involved in the malignant transformation of neoplastic cells and the understanding of the mechanisms that regulate these processes is undoubtedly a key objective for the development of new and more targeted therapies. RAF-kinase inhibitor protein (RKIP) is an endogenous tumour suppressor protein that affects tumour cell survival, proliferation, and metastasis. RKIP might serve as an early tumour biomarker since it exhibits significantly different expression levels in various cancer histologies and it is often lost during metastatic progression. In this review, we discuss the specific impact of transcriptional, post-transcriptional and post-translational regulation of expression and activation/inhibition of RKIP and focus on those tumours for which experimental data on all these factors are available. In this way, we could select how these processes cooperate with RKIP expression in (1) Lung cancer; (2) Colon cancer, (3) Breast cancer; (4) myeloid neoplasm and Multiple Myeloma, (5) Melanoma and (6) clear cell Renal Cell Carcinoma. Furthermore, since RKIP seems to be a key marker of the development of several tumours and it may be assessed easily in various biological fluids, here we discuss the potential role of RKIP dosing in more accessible biological matrices other than tissues. Moreover, this objective may intercept the still unmet need to identify new and more accurate markers for the early diagnosis and prognosis of many tumours.

FOXP3+ regulatory T cells and the immune escape in solid tumours

FOXP3+ regulatory T (Treg) cells play critical roles in establishing the immunosuppressive tumour microenvironment, which is achieved and dynamically maintained with the contribution of various stromal and immune cell subsets. However, the dynamics of non-lymphoid FOXP3+ Treg cells and the mutual regulation of Treg cells and other cell types in solid tumour microenvironment remains largely unclear. In this review, we summarize the latest findings on the dynamic connections and reciprocal regulations of non-lymphoid Treg cell subsets in accordance with well-established and new emerging hallmarks of cancer, especially on the immune escape of tumour cells in solid tumours. Our comprehension of the interplay between FOXP3+ Treg cells and key hallmarks of cancer may provide new insights into the development of next-generation engineered T cell-based immune treatments for solid tumours.

Lactate Metabolism-Associated lncRNA Pairs: A Prognostic Signature to Reveal the Immunological Landscape and Mediate Therapeutic Response in Patients With Colon Adenocarcinoma

Background

Lactate metabolism is critically involved in the tumor microenvironment (TME), as well as cancer progression. It is important to note, however, that lactate metabolism-related long non-coding RNAs (laRlncRNAs) remain incredibly understudied in colon adenocarcinoma (COAD).

Methods

A gene expression profile was obtained from the Cancer Genome Atlas (TCGA) database to identify laRlncRNA expression in COAD patients. A risk signature with prognostic value was identified from TCGA and Gene Expression Omnibus (GEO) cohort based on laRlncRNA pairs by the least absolute shrinkage and selection operator (LASSO) and Cox regression analyses. Quantitative real-time polymerase chain reaction (qRT-PCR) and functional experiments were carried out to verify the expression of laRlncRNAs in COAD. The relationship of laRlncRNA pairs with immune landscape as well as the sensitivity of different therapies was explored.

Results

In total, 2378 laRlncRNAs were identified, 1,120 pairs of which were studied to determine their prognostic validity, followed by a risk signature established based on the screened 5 laRlncRNA pairs. The laRlncRNA pairs-based signature provided a better overall survival (OS) prediction than other published signatures and functioned as a prognostic marker for COAD patients. According to the calculated optimal cut-off point, patients were divided into high- and low-risk groups. The OS of COAD patients in the high-risk group were significantly shorter than that of those in the low-risk group (P=4.252e-14 in the TCGA cohort and P=2.865-02 in the GEO cohort). Furthermore, it remained an effective predictor of survival in strata of gender, age, TNM stage, and its significance persisted after univariate and multivariate Cox regressions. Additionally, the risk signature was significantly correlated with immune cells infiltration, tumor mutation burden (TMB), microsatellite instability (MSI) as well as immunotherapeutic efficacy and chemotherapy sensitivity. Finally, one of the laRlncRNA, LINC01315, promotes proliferation and migration capacities of colon cancer cells.

Conclusion

The newly identified laRlncRNAs pairs-based signature exhibits potential effects in predicting prognosis, deciphering patients’ immune landscape, and mediating sensitivity to immunotherapy and chemotherapy. Findings in our study may provide evidence for the role of laRlncRNAs pairs as novel prognostic biomarkers and potentially individualized therapy targets for COAD patients.

UHMK1 aids colorectal cancer cell proliferation and chemoresistance through augmenting IL-6/STAT3 signaling

UHMK1, a serine/threonine kinase with a U2AF homology motif, is implicated in RNA processing and protein phosphorylation. Increasing evidence has indicated its involvement in tumorigenesis. However, it remains to be elucidated whether UHMK1 plays a role in the development of colorectal cancer (CRC). Here, we demonstrated that UHMK1 was frequently upregulated in CRC samples compared with adjacent normal tissue and high expression of UHMK1 predicted poor outcomes. Knockdown of UHMK1 by siRNAs restrained CRC cell proliferation and increased oxaliplatin sensitivity, whereas overexpression of UHMK1 promoted CRC cell growth and oxaliplatin resistance, suggesting that UHMK1 plays important oncogenic roles in CRC. Mechanistically, we showed that UHMK1 had a significant effect on IL6/STAT3 signaling by interacting with STAT3. The interaction of UHMK1 with STAT3 enhanced STAT3 activity in regulating gene transcription. Furthermore, we found that STAT3 could in turn transcriptionally activate UHMK1 expression in CRC cells. The complementary experiments for cell growth and oxaliplatin resistance indicated the interdependent relationship between UHMK1 and STAT3. Thus, these collective findings uncovered a new UHMK1/STAT3 positive feedback regulatory loop contributing to CRC development and chemoresistance.

A silica-based antioxidant nanoparticle for oral delivery of Camptothecin which reduces intestinal side effects while improving drug efficacy for colon cancer treatment

Camptothecin (CPT) is a potent anticancer agent for the treatment of colorectal cancer; however, it exhibits some limitations, including poor solubility, low stability, and low bioavailability via oral administration, which restrict its usability in clinical treatments. In addition, overproduction of reactive oxygen species (ROS) during chemotherapy induces drug resistance and severe intestinal side effects. In this study, silica-installed ROS scavenging nanoparticles (siRNP) with 50-60 nm in diameter were employed to overcome the aforementioned drawbacks of CPT. The solubility of CPT was significantly improved by incorporating it into the core of the nanoparticle, forming CPT-loaded siRNP (CPT@siRNP). The anticancer activity of CPT@siRNP against colorectal cancer cells (C-26) in vitro was significantly improved as compared to free CPT through higher efficiency of intracellular internalization and induction of apoptosis. Owing to its antioxidant properties, CPT@siRNP reduced cytotoxicity to normal endothelial cells, which was in sharp contrast to the high toxicity of free CPT. Oral administration of CPT and CPT@siRNP to the C-26 tumor-bearing mice exhibited antitumor activity, accompanied by effective suppression of tumor growth. Although CPT treatment suppressed tumor progression, it caused severe side effects, including intestinal damage and significant bodyweight loss. Interestingly, such noticeable side effects were not observed in the mice treated with CPT@siRNP, and the effect of tumor growth inhibition tended to be similar to or higher than that of CPT treatment. The results obtained in this study indicate that CPT@siRNP is a potential therapeutic nanomedicine for the treatment of colon cancer. STATEMENT OF SIGNIFICANCE: Here we employed silica-containing antioxidant nanoparticle (siRNP) as promising oral delivery nanocarrier of campothecin (CPT) to treat colon cancer. The design of siRNP via covalent conjugation of antioxidant nitroxide radicals and the silanol groups in the polymer backbone contributes to a significant increase in the absorption of hydrophobic drug molecules inside the core and enhances the stability of nanoparticles in the gastrointestinal environment for oral drug delivery. CPT-loaded siRNP (CPT@siRNP) significantly improved solubility of CPT. As compared to free CTP, the CPT@siRNP treatment showed a significantly higher toxicity to colon cancer cell, inhibition of cancer cell migration, and induction of apopotosis. With the antioxidant feature, siRNP also significantly suppressed the intestinal side effects caused by CPT treatment in tumor-bearing mouse model.

RKIP Pleiotropic Activities in Cancer and Inflammatory Diseases: Role in Immunity

Simple Summary

The human body consists of tissues and organs formed by cells. In each cell there is a switch that allows the cell to divide or not. In contrast, cancer cells have their switch on which allow them to divide and invade other sites leading to death. Over two decades ago, Doctor Kam Yeung, University of Toledo, Ohio, has identified a factor (RKIP) that is responsible for the on/off switch which functions normally in healthy tissues but is inactive or absent in cancers. Since this early discovery, many additional properties have been ascribed to RKIP including its role in inhibiting cancer metastasis and resistance to therapeutics and its role in modulating the normal immune response. This review describes all of the above functions of RKIP and suggesting therapeutics to induce RKIP in cancers to inhibit their growth and metastases as well as inhibit its activity to treat non-cancerous inflammatory diseases.

Abstract

Several gene products play pivotal roles in the induction of inflammation and the progression of cancer. The Raf kinase inhibitory protein (RKIP) is a cytosolic protein that exerts pleiotropic activities in such conditions, and thus regulates oncogenesis and immune-mediated diseases through its deregulation. Herein, we review the general properties of RKIP, including its: (i) molecular structure; (ii) involvement in various cell signaling pathways (i.e., inhibition of the Raf/MEK/ERK pathway; the NF-kB pathway; GRK-2 or the STAT-3 pathway; as well as regulation of the GSK3Beta signaling; and the spindle checkpoints); (iii) regulation of RKIP expression; (iv) expression’s effects on oncogenesis; (v) role in the regulation of the immune system to diseases (i.e., RKIP regulation of T cell functions; the secretion of cytokines and immune mediators, apoptosis, immune check point inhibitors and RKIP involvement in inflammatory diseases); and (vi) bioinformatic analysis between normal and malignant tissues, as well as across various immune-related cells. Overall, the regulation of RKIP in different cancers and inflammatory diseases suggest that it can be used as a potential therapeutic target in the treatment of these diseases.

Shikonin suppresses colon cancer cell growth and exerts synergistic effects by regulating ADAM17 and the IL‑6/STAT3 signaling pathway

Signal transducer and activator of transcription 3 (STAT3) activation is associated with drug resistance induced by anti-epidermal growth factor receptor (anti-EGFR) therapy in the treatment of colon cancer. Thus, the combined inhibition of EGFR and STAT3 may prove beneficial for this type of cancer. STAT3 has been proven to play a critical role in colon cancer initiation and progression, and is considered the primary downstream effector driven by interleukin-6 (IL-6). A disintegrin and metalloproteinase 17 (ADAM17), documented as an oncogene, catalyzes the cleavage of both EGF and IL-6R, inducing EGFR signaling and enabling IL-6 trans-signaling to activate STAT3 in a wide range of cell types to promote inflammation and cancer development. As a natural product, shikonin (SKN) has been found to function as an antitumor agent; however, its role in the regulation of ADAM17 and IL-6/STAT3 signaling in colon cancer cells remains unknown. In the present study, it was found that SKN inhibited colon cancer cell growth, suppressed both constitutive and IL-6-induced STAT3 phosphorylation, and downregulated the expression of ADAM17. ADAM17 expression was not altered in response to STAT3 knockdown, while IL-6-induced STAT3 activation did not induce ADAM17 transcripts. Furthermore, it was demonstrated that SKN did not affect the expression of key proteins involved in the maturation and degradation of ADAM17. SKN decreased ADAM17 expression possibly through reactive oxygen species (ROS)-mediated translational inhibition, as evidenced by the increased ADAM17 mRNA and phosphorylation levels of eukaryotic initiation factor 2α (eIF2α). The expression of ADAM17 and p-eIF2α was reversed by N-acetylcysteine (NAC, a ROS scavenger). Taken together, these results indicate that the concurrent inhibition of ADAM17 and IL-6/STAT3 signaling by SKN may synergistically contribute to the suppression of colon cancer cell growth.

Prognostic Value of N6-Methyladenosine-Related lncRNAs in Early-Stage Colorectal Cancer: Association With Immune Cell Infiltration and Chemotherapeutic Drug Sensitivity

Purpose: Accumulating evidence indicates that N6-methyladenosine-related long non-coding RNAs (m6A-related lncRNAs) play a crucial role in the occurrence and development of several cancers. We aimed to explore the potential role of m6A-related lncRNA signatures in predicting prognosis for early-stage (stages I and II) colorectal cancer (CRC).

Methods: m6A-related lncRNA data were obtained from The Cancer Genome Atlas. Univariate Cox regression analysis was used to screen for prognostic m6A-related lncRNAs. Immune characteristics were analyzed in different subgroups created via unsupervised clustering analysis. Next, patients were randomly divided into training and test cohorts. In the training cohort, least absolute shrinkage and selection operator (LASSO) regression was performed to establish a prognostic model. The predictive value of the signature was evaluated in the training and test cohorts. Drug sensitivity was also examined.

Results: A total of 1,478 m6A-related lncRNAs were identified. Two subgroups were created based on the expression of seven prognostic m6A-related lncRNAs. Prognosis was worse for cluster 1 than for cluster 2, and cluster 1 was characterized by increased numbers of M2 macrophages, decreased numbers of memory B cells, and higher expression of checkpoint genes when compared with cluster 2. Five m6A-related lncRNAs were selected to establish a risk prediction signature via LASSO regression. The 3 years overall survival (OS) was higher in the low-risk group than in the high-risk group. The area under the curve at 1, 2, and 3 years was 0.929, 0.954, and 0.841 in the training cohort and 0.664, 0.760, and 0.754 in the test cohort, respectively. Multivariate Cox regression analysis suggests that the risk score was an independent predictor of OS in both the training and test cohorts. A prognostic nomogram based on the five m6A-related lncRNAs and their clinical features was built and verified. The high-risk group was more sensitive to chemotherapeutic drugs (camptothecin and cisplatin) than the low-risk group.

Conclusion: We identified two molecular subgroups of early-stage CRC with unique immune features based on seven prognostic m6A-related lncRNAs. Subsequent analyses demonstrated the usefulness of a five m6A-related lncRNA signature as a potential indicator of prognosis in patients with early-stage CRC.

Regulation on tumor metastasis by Raf kinase inhibitory protein: New insight with reactive oxygen species signaling

Targeted therapy aiming at the metastatic signal pathway, such as that triggered by receptor tyrosine kinase (RTK), for the prevention of tumor progression is promising. However, RTK-based targeted therapy frequently suffered from drug resistance due to the co-expression of multiple growth factor receptors that may raise compensatory secondary signaling and acquired mutations after treatment. One alternative strategy is to manipulate the common negative regulators of the RTK signaling. Among them, Raf kinase inhibitory protein (RKIP) is highlighted and focused on this review. RKIP can associate with Raf-1, thus suppressing the downstream mitogen-activated protein kinase (MAPK) cascade. RKIP also negatively regulates other metastatic signal molecules including NF-κB, STAT3, and NOTCH1. In general, RKIP achieves this task via associating and blocking the activity of the critical molecules on upstream of the aforementioned pathways. One novel RKIP-related signaling involves reactive oxygen species (ROS). In our recent report, we found that PKCδ-mediated ROS generation may interfere with the association of RKIP with heat shock protein 60 (HSP60)/MAPK complex via oxidation of HSP60 triggered by the tumor promoter 12-O-tetradecanoyl-phorbol-13-acetate. The departure of RKIP may impact the downstream MAPK in two aspects. One is to trigger the Mt→cytosol translocation of HSP60 coupled with MAPKs. The other is to change the conformation of HSP60, favoring more efficient activation of the associated MAPK by upstream kinases in cytosol. It is worthy of investigating whether various RTKs capable of generating ROS can drive metastatic signaling via affecting RKIP in the same manner.

Expression and Prognostic Characteristics of Ferroptosis-Related Genes in Colon Cancer

Ferroptosis is a new type of programmed cell death, which occurs with iron dependence. Previous studies have showed that ferroptosis plays an important regulatory role in the occurrence and development of tumors. Colon cancer is one of the major morbidities and causes of mortality in the world. This study used RNA-seq and colon cancer clinical data to explore the relationship between ferroptosis-related genes and colon cancer. Based on the fifteen prognostic ferroptosis-related genes, two molecular subgroups of colon cancer were identified. Surprisingly, we also found cluster2 was characterized by lower mutation burden and expression of checkpoint genes, better survival, and higher expression of NOX1. Moreover, cluster2 has fewer BRAF mutations. We also found the expression of NOX1 is related to the status of BRAF. Finally, using 15 ferroptosis-related genes from The Cancer Genome Atlas cohort, we constructed a prognosis model, and this model may be used to predict the prognosis of patients in clinics.

Revisiting Platinum-Based Anticancer Drugs to Overcome Gliomas

Although there are many patients with brain tumors worldwide, there are numerous difficulties in overcoming brain tumors. Among brain tumors, glioblastoma, with a 5-year survival rate of 5.1%, is the most malignant. In addition to surgical operations, chemotherapy and radiotherapy are generally performed, but the patients have very limited options. Temozolomide is the most commonly prescribed drug for patients with glioblastoma. However, it is difficult to completely remove the tumor with this drug alone. Therefore, it is necessary to discuss the potential of anticancer drugs, other than temozolomide, against glioblastomas. Since the discovery of cisplatin, platinum-based drugs have become one of the leading chemotherapeutic drugs. Although many studies have reported the efficacy of platinum-based anticancer drugs against various carcinomas, studies on their effectiveness against brain tumors are insufficient. In this review, we elucidated the anticancer effects and advantages of platinum-based drugs used in brain tumors. In addition, the cases and limitations of the clinical application of platinum-based drugs are summarized. As a solution to overcome these obstacles, we emphasized the potential of a novel approach to increase the effectiveness of platinum-based drugs.

RAF Kinase Inhibitor Protein in Myeloid Leukemogenesis

RAF kinase inhibitor protein (RKIP) is an essential regulator of intracellular signaling. A somatic loss of RKIP expression is a frequent event in solid human cancers, and a role of RKIP as metastasis-suppressor is widely accepted nowadays. Recently, RKIP loss has been described in acute myeloid leukemia (AML) and a series of other myeloid neoplasias (MNs). Functional in vitro and in vivo experiments revealed that RKIP is an essential player within the development of these liquid tumors; however, the respective role of RKIP seems to be complex and multi-faceted. In this review, we will summarize the current knowledge about RKIP in myeloid leukemogenesis. We will initially describe its involvement in physiologic hematopoiesis, and will then proceed to discuss its role in the development of AML and other MNs. Finally, we will discuss potential therapeutic implications arising thereof.

Current Status of Raf Kinase Inhibitor Protein (RKIP) in Lung Cancer: Behind RTK Signaling

Lung cancer is the most deadly neoplasm with the highest incidence in both genders, with non-small cell lung cancer (NSCLC) being the most frequent subtype. Somatic mutations within the tyrosine kinase domain of the epidermal growth factor receptor (EGFR) gene are key drivers of NSCLC progression, with EGFR inhibitors being particularly beneficial for patients carrying the so-called “EGFR-sensitizing mutations”. However, patients eventually acquire resistance to these EGFR inhibitors, and a better knowledge of other driven and targetable proteins will allow the design of increasingly accurate drugs against patients’ specific molecular aberrations. Raf kinase inhibitory protein (RKIP) is an important modulator of relevant intracellular signaling pathways, including those controlled by EGFR, such as MAPK. It has been reported that it has metastasis suppressor activity and a prognostic role in several solid tumors, including lung cancer. In the present review, the potential use of RKIP in the clinic as a prognostic biomarker and predictor of therapy response in lung cancer is addressed.

Oxaliplatin regulates myeloid-derived suppressor cell-mediated immunosuppression via downregulation of nuclear factor-κB signaling

Myeloid‐derived suppressor cells (MDSCs) represent one of the major types of immunoregulatory cells present under abnormal conditions, including cancer. These cells are characterized by their immature phenotype and suppressive effect on various immune effectors. In both human and mouse, there are two main subsets of MDSCs: polymorphonuclear (PMN)‐MDSCs and mononuclear (Mo)‐MDSCs. Thus, strategies to regulate MDSC‐mediated immunosuppression could result in the enhancement of anticancer immune responses. Oxaliplatin, a platinum‐based anticancer agent, is widely used in clinical settings. It is known to induce cell death by interfering with double‐stranded DNA and interrupting its replication and transcription. In this study, we found that oxaliplatin has the potential to regulate MDSC‐mediated immunosuppression in cancer. First, oxaliplatin selectively depleted MDSCs, especially Mo‐MDSCs, but only minimally affected T cells. In addition, sublethal doses of oxaliplatin eliminated the immunosuppressive capacity of MDSCs and induced the differentiation of MDSCs into mature cells. Oxaliplatin treatment diminished the expression of the immunosuppressive functional mediators arginase 1 (ARG1) and NADPH oxidase 2 (NOX2) in MDSCs, while an MDSC‐depleting agent, gemcitabine, did not downregulate these factors significantly. Oxaliplatin‐conditioned MDSCs had no tumor‐promoting activity in vivo. In addition, oxaliplatin modulated the intracellular NF‐κB signaling in MDSCs. Thus, oxaliplatin has the potential to be used as an immunoregulatory agent as well as a cytotoxic drug in cancer treatment.

Different responses of colorectal cancer cells to alternative sequences of cetuximab and oxaliplatin

Therapeutic protocols including EGFR antibodies in the context of oxaliplatin-based regimens have variable clinical effect in colorectal cancer. Here, we tested the effect of the EGFR antibody cetuximab in different sequential combinations with oxaliplatin on the growth of colorectal cancer cells in vitro and in vivo. Cetuximab reduced the efficacy of oxaliplatin when administered before oxaliplatin but provided additive effect when administered after oxaliplatin regardless of the KRAS or BRAF mutation status of the cells. Systemic gene expression and protein phosphorylation screens revealed alternatively activated pathways regulating apoptosis, cell cycle and DNA damage response. Functional assays indicated that cetuximab-induced arrest of the cells into the G1 phase of the cell cycle was associated with reduced responsiveness of the cells to subsequent treatment with oxaliplatin. In contrast, oxaliplatin-enhanced responsiveness to subsequent treatment with cetuximab was associated with increased apoptosis, inhibition of STAT3 activity and increased EGFR down-regulation. This preclinical study indicates that optimizing the sequence of administration may enhance the antitumor effect of combination therapy with EGFR antibodies and oxaliplatin.

RKIP: A Key Regulator in Tumor Metastasis Initiation and Resistance to Apoptosis: Therapeutic Targeting and Impact

RAF-kinase inhibitor protein (RKIP) is a well-established tumor suppressor that is frequently downregulated in a plethora of solid and hematological malignancies. RKIP exerts antimetastatic and pro-apoptotic properties in cancer cells, via modulation of signaling pathways and gene products involved in tumor survival and spread. Here we review the contribution of RKIP in the regulation of early metastatic steps such as epithelial⁻mesenchymal transition (EMT), migration, and invasion, as well as in tumor sensitivity to conventional therapeutics and immuno-mediated cytotoxicity. We further provide updated justification for targeting RKIP as a strategy to overcome tumor chemo/immuno-resistance and suppress metastasis, through the use of agents able to modulate RKIP expression in cancer cells.

Oxaliplatin disrupts pathological features of glioma cells and associated macrophages independent of apoptosis induction

INTRODUCTION

Emerging evidence suggests that effective treatment of glioblastoma (GBM), the most common and deadly form of adult primary brain cancer, will likely require concurrent treatment of multiple aspects of tumor pathobiology to overcome tumor heterogeneity and the complex tumor-supporting microenvironment. Recent studies in non-central nervous system (CNS) tumor cells have demonstrated that oxaliplatin (OXA) can induce multi-faceted anti-tumor effects, in particular at drug concentrations below those required to induce apoptosis. These findings motivated re-investigation of OXA for the treatment of GBM.

METHODS

The effects of OXA on murine KR158 and GL261 glioma cells including cell growth, cell death, inhibition of signal transducer and activator of transcription (STAT) activity, O-6-methylguanine-DNA methyltransferase (MGMT) expression, and immunogenic cell death (ICD) initiation, were evaluated by cytotoxicity assays, Western blot analysis, STAT3-luciferase reporter assays, qRT-PCR assays, and flow cytometry. Chemical inhibitors of endoplasmic reticulum (ER) stress were used to investigate the contribution of this cell damage response to the observed OXA effects. The effect of OXA on bone marrow-derived macrophages (BMDM) exposed to glioma conditioned media (GCM) was also analyzed by Western blot analysis.

RESULTS

We identified the OXA concentration threshold for induction of apoptosis and from this determined the drug dose and treatment period for sub-cytotoxic treatments of glioma cells. Under these experimental conditions, OXA reduced STAT3 activity, reduced MGMT levels and increased temozolomide sensitivity. In addition, there was evidence of immunogenic cell death (elevated EIF2α phosphorylation and calreticulin exposure) following prolonged OXA treatment. Notably, inhibition of ER stress reversed the OXA-mediated inhibition of STAT3 activity and MGMT expression in the tumor cells. In BMDMs exposed to GCM, OXA also reduced levels of phosphorylated STAT3 and decreased expression of Arginase 1, an enzyme known to contribute to pro-tumor functions in the tumor-immune environment.

CONCLUSIONS

OXA can induce notable multi-faceted biological effects in glioma cells and BMDMs at relatively low drug concentrations. These findings may have significant therapeutic relevance against GBM and warrant further investigation.

Systematic literature review of IL-6 as a biomarker or treatment target in patients with gastric, bile duct, pancreatic and colorectal cancer

Gastrointestinal cancer (GI) is a major health problem. Patients with gastric, pancreatic, colorectal, bile duct and gall bladder cancer often have advanced disease at the time of diagnosis and are generally difficult to cure, resulting in a dismal prognosis for most patients. Inflammation plays an important role in the development and growth of cancer, which has led to a growing interest in the pro-inflammatory cytokine interleukin 6 (IL-6). The aim of the present review was to evaluate the clinical use of IL-6 as a biomarker or therapeutic target in patients with GI cancer. We did a systematic review of studies (1993-2018), to assess the clinical use of IL-6 as a diagnostic, prognostic or predictive tumor biomarker or as a potential therapeutic target. This review includes 48 studies and 5316 patients. Circulating IL-6 levels appear to be an independent prognostic biomarker in patients with GI cancer, with high IL-6 levels associated with short overall survival (OS). The results for colorectal cancer were too ambiguous to give conclusive results. IL-6 seemed to be a marker for some of the clinical characteristics of GI cancer, and may have a role in the diagnostic workup in general practice. No published studies have examined the use of IL-6 as a therapeutic target in pancreatic, gastric, bile duct or colorectal cancer. In conclusion, high circulating IL-6 was associated with short OS in most studies in GI cancer patients. Whether inhibition of IL-6 would decrease GI cancer symptoms and increase quality of life is unknown.

Inhibition of the Raf-1 kinase inhibitory protein (RKIP) by locostatin induces cell death and reduces the CXCR4-mediated migration of chronic lymphocytic leukemia cells

The Raf-1 kinase inhibitory protein (RKIP) is an important regulatory element in multiple signaling pathways, including MAPK-ERK1/2. We investigated whether targeted disruption of RKIP is a therapeutic option for chronic lymphocytic leukemia (CLL). The RKIP inhibitor locostatin-induced apoptosis of CLL cells, irrespective of poor prognostic indications or treatment history. Locostatin down-regulated MAPK-ERK1/2 and AKT phosphorylation, decreased expression of the chemokine receptor CXCR4 (p = .04) and reduced the migratory capacity of CLL cells toward stroma-derived factor 1α (SDF-1α, p = .02). Immuno-blotting and immuno-precipitation showed that RKIP is constitutively phosphorylated and highly expressed in CLL cells and that the actions of locostatin may be mediated by binding of G-protein receptor kinase-2 (GRK2) to MEK1 and AKT. Collectively, our data suggest that inhibition of RKIP may be effective against CLL, reducing the survival and migratory capacity of the leukemic cells through down-regulation of MAPK-ERK1/2 and AKT-mediated signaling.

Blocking fatty acid-fueled mROS production within macrophages alleviates acute gouty inflammation

Gout is the most common inflammatory arthritis affecting men. Acute gouty inflammation is triggered by monosodium urate (MSU) crystal deposition in and around joints that activates macrophages into a proinflammatory state, resulting in neutrophil recruitment. A complete understanding of how MSU crystals activate macrophages in vivo has been difficult because of limitations of live imaging this process in traditional animal models. By live imaging the macrophage and neutrophil response to MSU crystals within an intact host (larval zebrafish), we reveal that macrophage activation requires mitochondrial ROS (mROS) generated through fatty acid oxidation. This mitochondrial source of ROS contributes to NF-κB-driven production of IL-1β and TNF-α, which promote neutrophil recruitment. We demonstrate the therapeutic utility of this discovery by showing that this mechanism is conserved in human macrophages and, via pharmacologic blockade, that it contributes to neutrophil recruitment in a mouse model of acute gouty inflammation. To our knowledge, this study is the first to uncover an immunometabolic mechanism of macrophage activation that operates during acute gouty inflammation. Targeting this pathway holds promise in the management of gout and, potentially, other macrophage-driven diseases.

Effects of thalidomide on growth and VEGF-A expression in SW480 colon cancer cells

Lymphatic and hematogenous spread are the most common ways for tumors to metastasize. Angiogenesis is essential for tumor growth and metastasis. Vascular endothelial growth factor (VEGF) particularly VEGF-A is important in the process of angiogenesis. The current research has indicated that thalidomide (THD) may be able to inhibit angiogenesis, stimulate the activity of the immune system and inhibit the adherence of cancer cells to stromal cells. These changes may lead to suppression of tumor occurrence and development. To date, to the best of our knowledge, the effects of THD on colon cancer SW480 cells have not been reported. In the present study, the effects of THD and a combination of THD and oxaliplatin (L-OHP) on the proliferation of SW480 cells have been investigated. Furthermore, the expression of VEGF-A and hypoxia-inducible factor 1 (HIF-1) was analyzed using MTT assay, quantitative polymerase chain reaction and western blot analysis. The results indicated that THD was able to inhibit SW480 cells in dose-and-time dependent manner and inhibit the expression of VEGF-A and HIF-1α. Furthermore, treatment with THD and L-OHP had synergistic inhibitory effect, which may provide a novel treatment strategy for advanced colorectal cancer.

Oxaliplatin induces muscle loss and muscle-specific molecular changes in Mice

INTRODUCTION

Muscle wasting is a frequent, debilitating complication of cancer. The impact of colorectal cancer chemotherapeutic oxaliplatin on the development of muscle loss and associated molecular changes is of clinical importance.

METHODS

C57BL/6J male mice were treated with oxaliplatin. Total body weights were measured and behavioral studies performed. Hindlimb muscle weights (gastrocnemius and soleus) were recorded in conjunction with gene and protein expression analysis.

RESULTS

Oxaliplatin-treated mice displayed reduced weight gain and behavioral deficits. Mice treated over a shorter course had significantly increased STAT3 phosphorylation in gastrocnemius muscles. Mice receiving extended oxaliplatin treatment demonstrated reduced hindlimb muscle mass with upregulation of myopathy-associated genes Foxo3, MAFbx, and Bnip3.

DISCUSSION

The findings suggest that oxaliplatin treatment can directly disrupt skeletal muscle homeostasis and promote muscle loss, which may be clinically relevant in the context of targeting fatigue and weakness in cancer patients. Muscle Nerve 57: 650-658, 2018.

Mucin 2 silencing promotes colon cancer metastasis through interleukin-6 signaling

Downregulation of Mucin 2 (MUC2) expression is associated with early carcinogenesis events in colon cancer. MUC2 plays a role in the progression of colon cancer, and reduced MUC2 protein expression correlates with increased interleukin-6 (IL-6) expression. However, the interaction between MUC2 and IL-6 in colorectal cancer metastasis remains unclear. We systematically analyzed MUC2 and IL-6 expression and determined the survival of cancer patients with high or low MUC2 and IL-6 expression using the Oncomine and PrognoScan databases, respectively. This analysis identified downregulation of MUC2 and overexpression of IL-6 in colon cancer but not in normal colon tissue, and this expression pattern was correlated with poor survival of colon cancer patients. We examined the effects of MUC2 on colon cancer metastasis and used vector-mediated application of short hairpin RNA (shRNA) to suppress MUC2 expression. MUC2 suppressed the migration of colon cancer cells in vitro and dramatically diminished liver metastases in vivo. Treatment with IL-6 increased signal transducer and activator of transcription 3 (STAT3) phosphorylation, promoted checkpoint kinase 2 (Chk2) activation, attenuated cAMP response element-binding protein (CREB) phosphorylation, and suppressed E-cadherin protein expression in MUC2-silenced HT-29 cancer cells. Most importantly, MUC2 is a potential prognostic indicator for colon cancer.

Overexpression of RKIP and its cross-talk with several regulatory gene products in multiple myeloma

Multiple myeloma (MM) is a clonal plasma-cell neoplastic disorder arising from an indolent premalignant disease known as monoclonal gammopathy of undetermined significance (MGUS). MM is a biologically complex heterogeneous disease reflected by its variable clinical responses of patients receiving the same treatment. Therefore, a molecular identification of stage-specific biomarkers will support a more individualized precise diagnostic/prognostic approach, an effective therapeutic regime, and will assist in the identification of novel therapeutic molecular targets. The metastatic suppressor/anti-resistance factor Raf-1 kinase inhibitor protein (RKIP) is poorly expressed in the majority of cancers and is often almost absent in metastatic tumors. RKIP inhibits the Raf/MEK/ERK1/2 and the NF-κB pathways. Whereby all tumors examined exhibited low levels of RKIP, in contrast, our recent findings demonstrated that RKIP is overexpressed primarily in its inactive phosphorylated form in MM cell lines and patient-derived tumor tissues. The underlying mechanism of RKIP overexpression in MM, in contrast to other tumors, is not known. We examined transcriptomic datasets on Oncomine platform (Life Technologies) for the co-expression of RKIP and other gene products in both pre-MM and MM. The transcription of several gene products was found to be either commonly overexpressed (i.e., RKIP, Bcl-2, and DR5) or underexpressed (i.e., Bcl-6 and TNFR2) in both pre-MM and MM. Noteworthy, a significant inverse correlation of differentially expressed pro-apoptotic genes was observed in pre-MM: overexpression of Fas and TNF-α and underexpression of YY1 versus expression of anti-apoptotic genes in MM: overexpression of YY1 and underexpression of Fas and TNF-α. Based on the analysis on mRNA levels and reported studies on protein levels of the above various genes, we have constructed various schemes that illustrate the possible cross-talks between RKIP (active/inactive) and the identified gene products that underlie the mechanism of RKIP overexpression in MM. Clearly, such cross-talks would need to be experimentally validated in both MM cell lines and patient-derived tumor tissues. If validated, the differential molecular signatures between pre-MM and MM might lead to a more precise diagnosis/prognosis of the disease and disease stages and will also identify novel molecular therapeutic targets for pre-MM and MM.

Reduced RKIP expression levels are associated with frequent non-small cell lung cancer metastasis and STAT3 phosphorylation and activation

The current study examined the role of Raf kinase inhibitor protein (RKIP) in non-small cell lung cancer (NSCLC) metastasis. A total of 100 patients with NSCLC were recruited following pathological diagnosis in the First Affiliated Hospital of Bengbu Medical College. The patients were classified and statistically analyzed according to their clinicopathological characteristics and tumor-node-metastasis stage. Paired tumor tissue and adjacent non-tumor tissue samples were subject to pathological diagnosis and western blot analysis. Transient transfection and lentivirus particle vector-mediated RKIP overexpression, small interfering RNA-mediated silencing, Transwell assays and immunocytochemistry methods were employed to elucidate the role and underlying mechanisms of RKIP and the Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway in NSCLC metastasis. Furthermore, in order to examine the in vivo effects of RKIP, recombinant lentivirus particles containing the RKIP gene were administrated in a mouse NSCLC tumor model via tail vein injection. The results revealed reduced RKIP expression levels in NSCLC tissue compared with corresponding non-cancer tissue. Additionally, RKIP expression levels were inversely associated with NSCLC intra-lung, lymph node and long-distance metastasis. The results also indicated that RKIP was able to block STAT3 activation via phosphorylation and inhibit NSCLC-cell metastasis in vitro. Furthermore, RKIP knockdown was able to promote STAT3 phosphorylation and cell metastasis in NSCLC cell lines. During in vivo experiments, RKIP overexpression was able to suppress xenograft tumor metastasis in nude mice. Therefore, RKIP may be an important factor in cancer cell metastasis in patients with NSCLC, and RKIP may inhibit NSCLC-cell invasion by blocking the activation of the JAK/STAT3 signaling pathway.

Autophagy impacts on oxaliplatin-induced hepatocarcinoma apoptosis via the IL-17/IL-17R-JAK2/STAT3 signaling pathway

The interleukin (IL)-17/IL-17 receptor (IL-17R) complex has been shown to be important for the regulation of inflammation; however, its role in the regulation of tumor processes has recently emerged as a research focus. The present study demonstrated that oxaliplatin was able to increase the levels of IL-17/IL-17R in hepatocellular carcinoma (HCC) patients and cells lines, and that it had important roles in reducing the susceptibility of the cells to oxaliplatin-induced apoptosis. Furthermore, the expression of autophagy-related proteins was induced by IL-17/IL-17R and autophagy was shown to induce resistance to oxaliplatin in HCC. In addition, the janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) pathway was shown to be an important pathway in the induction of autophagy in response to oxaliplatin. Autopjhagy was inhibited by 3-methyladenine and JAK2/STAT3 signaling was blocked by AG490, which induced apoptosis in SMMC7721 cells treated with oxaliplatin. The results of the present study may help to elucidate the mechanism underlying the role of IL-17/IL-17R-induced autophagy in the chemoresistance of HCC, as well as help to establish and develop measures to overcome chemoresistance in HCC.

Inverse correlation between the metastasis suppressor RKIP and the metastasis inducer YY1: Contrasting roles in the regulation of chemo/immuno-resistance in cancer

Several gene products have been postulated to mediate inherent and/or acquired anticancer drug resistance and tumor metastasis. Among these, the metastasis suppressor and chemo-immuno-sensitizing gene product, Raf Kinase Inhibitor Protein (RKIP), is poorly expressed in many cancers. In contrast, the metastasis inducer and chemo-immuno-resistant factor Yin Yang 1 (YY1) is overexpressed in many cancers. This inverse relationship between RKIP and YY1 expression suggests that these two gene products may be regulated via cross-talks of molecular signaling pathways, culminating in the expression of different phenotypes based on their targets. Analyses of the molecular regulation of the expression patterns of RKIP and YY1 as well as epigenetic, post-transcriptional, and post-translational regulation revealed the existence of several effector mechanisms and crosstalk pathways, of which five pathways of relevance have been identified and analyzed. The five examined cross-talk pathways include the following loops: RKIP/NF-κB/Snail/YY1, p38/MAPK/RKIP/GSK3β/Snail/YY1, RKIP/Smurf2/YY1/Snail, RKIP/MAPK/Myc/Let-7/HMGA2/Snail/YY1, as well as RKIP/GPCR/STAT3/miR-34/YY1. Each loop is comprised of multiple interactions and cascades that provide evidence for YY1's negative regulation of RKIP expression and vice versa. These loops elucidate potential prognostic motifs and targets for therapeutic intervention. Chiefly, these findings suggest that targeted inhibition of YY1 by specific small molecule inhibitors and/or the specific induction of RKIP expression and activity are potential therapeutic strategies to block tumor growth and metastasis in many cancers, as well as to overcome anticancer drug resistance. These strategies present potential alternatives for their synergistic uses in combination with low doses of conventional chemo-immunotherapeutics and hence, increasing survival, reducing toxicity, and improving quality of life.

Glycoprotein 130 is associated with adverse postoperative clinical outcomes of patients with late-stage non-metastatic gastric cancer

The interaction of glycoprotein 130 (gp130) with the cytokines of Interleukin-6 (IL-6) family has proved to play a crucial part in several cancers. Our current study is designed to discover the clinical prognostic significance of gp130 in non-metastatic gastric cancer. We examined intratumoral gp130 expression in retrospectively enrolled 370 gastric cancer patients who underwent radical gastrectomy with standard D2 lymphadenectomy at Zhongshan Hospital of Fudan University during 2007 and 2008 by immunohistochemical staining. The expression of gp130 was significantly correlated with T classification, N classification and TNM stage (P = 0.003, P < 0.001 and P < 0.001, respectively; T, N, TNM refers to Tumor Invasion, Regional lymph node metastasis and Tumor Node Metastasis, respectively). Elevated intratumoral gp130 expression implied unfavourable overall survival (OS) (P < 0.001) and disease-free survival (DFS) (P < 0.001), respectively. Furthermore, among TNM II and III gp130-high patients, those who were treated with 5-fluorouracil (5-FU) based adjuvant chemotherapy had better OS (P < 0.001). The generated nomogram performed well in predicting the 3- and 5-year OS of gastric cancer patients. The incorporation of gp130 into contemporary TNM staging system would be of great significance to improve the current individual risk stratification. These findings contribute to better clinical management for those patients who would benefit from adjuvant chemotherapy.

Prognostic value of phosphorylated Raf kinase inhibitory protein at serine 153 and its predictive effect on the clinical response to radiotherapy in nasopharyngeal carcinoma

BACKGROUND

Radiation is an effective treatment against nasopharyngeal carcinoma (NPC). However, radioresistance-induced locoregional recurrence remains as a major cause of treatment failure. Therefore, radiosensitivity indicators prior to treatment should be developed to screen radioresistant patients. Previous studies revealed that RKIP (Raf kinase inhibitor protein) is associated with NPC prognosis and radiosensitivity. However, the relationship of p-Ser153 RKIP (RKIP in a phosphorylated form at residue serine153) expression with the effect of radiation and prognosis of NPC patients is not elucidated. Thus, these clinical implication of the phosphorylated RKIP in NPC has yet to be described.

METHODS

The effect of p-Ser153 RKIP on locoregional relapse-free survival (LRRFS) was first analyzed in a retrospective cohort of NPC patients without distant metastasis at initial diagnosis. They received radical intensity-modulated radiotherapy alone. Of 180 patients were enrolled in the ongoing matched pair study. The patients were re-classified into radioresistant group or radiosensitive group on the basis of the specified criteria. Patients in the two groups were matched in terms of radiosensitivity-related factors. p-Ser153 RKIP was examined by immunohistochemical staining on a NPC tissue microarray before radiotherapy. The relationship between the expression of p-Ser153 RKIP and the effect of radiotherapy was also analyzed.

RESULTS

In this study, a retrospective cohort with 733 cases who received radical radiotherapy alone was established. Using the cohort, we validated that the p-Ser153 RKIP expression observed through immunohistochemical staining in a pretreatment NPC tissue microarray was an independent prognostic factor of LRRFS and OS; we also confirmed that endemic patients with a positive p-Ser153 RKIP expression benefited from irradiation alone in terms of locoregional relapse-free survival. A total of 180 patients were enrolled in a matched pair study. Both groups were well matched in terms of radiosensitivity-related factors. On the basis of the p-Ser153 RKIP expression, we predicted the following data: 80.0 % sensitivity, 73.3 % specificity, 76.7 % accuracy, 75.0 % positive predictive value, and 78.6 % negative predictive value.

CONCLUSIONS

Our results revealed for the first time that positive p-Ser153 RKIP expression was a favorable prognostic factor. It was also positively correlated with the radiosensitivity of NPC. p-Ser153 RKIP could also be used as a biomolecular marker with good availability and authenticity to preliminarily screen NPC-related clinical radiosensitivity.

Overexpression of gelsolin reduces the proliferation and invasion of colon carcinoma cells

The enhanced motility of cancer cells via the remodeling of the actin cytoskeleton is crucial in the process of cancer cell invasion and metastasis. It was previously demonstrated that gelsolin (GSN) may be involved as a tumor or a metastasis suppressor, depending on the cell lines and model systems used. In the present study, the effect of GSN on the growth and invasion of human colon carcinoma (CC) cells was investigated using reverse transcription quantitative polymerase chain reaction and western blotting. It was observed that upregulation of the expression of GSN in human CC cells significantly reduced the invasiveness of these cells. The expression levels of GSN were observed to be reduced in CC cells, and the reduced expression level of GSN was often associated with a poorer metastasis-free survival rate in patients with CC (P=0.04). In addition, the overexpression of GSN inhibited the invasion of CC cells in vitro. Furthermore, GSN was observed to inhibit signal transducer and activator of transcription (STAT) 3 signaling in CC cells. Together, these results suggested that GSN is critical in regulating cytoskeletal events and inhibits the invasive and/or metastatic potential of CC cells. The results obtained in the present study may improve understanding of the functional and mechanistic links between GSN as a possible tumor suppressor and the STAT3 signaling pathway, with respect to the aggressive nature of CC. In addition, the present study demonstrated the importance of GSN in regulating the invasion and metastasis of CC cells at the molecular level, suggesting that GSN may be a potential predictor of prognosis and treatment success in CC.

Understanding perspectives of signalling mechanisms regulating PEBP1 function

Phosphatidylethanolamine-binding protein 1 (PEBP1), also known as Raf kinase inhibitor protein, belongs to PEBP family of proteins. It is known to interact with many proteins that are mainly involved in pathways that monitor cell proliferation and differentiation. PEBP1 in many cells interacts with several pathways, namely MAPK, GRK2, NF-кB, etc. that keeps the cell proliferation and differentiation in check. This protein is expressed by many cells in humans, including neurons where it is predominantly involved in production of choline acetyltransferase. Deregulated PEBP1 is known to cause cancer, diabetic nephropathy and neurodegenerative diseases like Alzheimer's and dementia. Recent research led to the discovery of many drugs that mainly target the interaction of PEBP1 with its partners. These compounds are known to bind PEBP1 in its conserved domain which abrogate its association with interacting partners in several different pathways. We outline here the latest developments in understanding of PEBP1 function in maintaining cell integrity. Copyright © 2016 John Wiley & Sons, Ltd.

SIGNIFICANCE OF THE STUDY

Phosphatidylethanolamine-binding protein is crucial in regulation of MAPK and PKC pathways. Its diverse roles, including regulating these pathways keep cell differentiation and proliferation in check. This review outlines some latest findings which greatly add to our current knowledge of phosphatidylethanolamine-binding protein.

Eriocalyxin B blocks human SW1116 colon cancer cell proliferation, migration, invasion, cell cycle progression and angiogenesis via the JAK2/STAT3 signaling pathway

Eriocalyxin B, a natural ent-kaurene diterpene compound, has been shown to prevent carcinogenesis and tumor development. However, little is known regarding the mechanism underlying the antitumor activity of Eriocalyxin B in human colon cancer. The aim of the present study was to examine the role of Eriocalyxin B in SW1116 cells, and to verify the hypothesis that the Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) signaling pathway may serve as a therapeutic target in human colon cancer treatment. Cell proliferation was measured with a Cell Counting kit‑8 assay, and the cell cycle was assessed by flow cytometry. Cell migration and invasion were measured by Transwell analysis. In addition, western blot analysis was performed to detect the protein expression levels in SW1116 cells treated with various concentrations of Eriocalyxin B. The results demonstrated that 1 µmol/l Eriocalyxin B was effective at inhibiting JAK2 and STAT3 phosphorylation, followed by the downregulation of JAK2 and STAT3 downstream target expression, which resulted in the inhibition of cell proliferation, migration, invasion and angiogenesis. Eriocalyxin B also suppressed the expression of proliferation‑associated protein (proliferating cell nuclear antigen) and angiogenesis‑associated proteins (vascular endothelial growth factor and vascular endothelial growth factor receptor 2), as well as that of migration- and invasion‑associated proteins (matrix metalloproteinase 2 and 9). These results suggested that Eriocalyxin B may suppress JAK2/STAT3 signaling, and thus act as a therapeutic or preventive agent in the treatment of human colon cancer.

RAF Kinase Inhibitory Protein Expression and Phosphorylation Profiles in Oral Cancers

Raf Kinase Inhibitory Protein (RKIP) expression has been profiled for a number of unique tissue cancers. However, certain tissues have not been explored, and oral and oropharyngeal cancers stand out as high priority targets, given their relatively high incidence, high morbidity rate, and in many cases, preventable nature. The purpose of this study was to examine changes in RKIP expression and phosphorylation in tissues resected from oral cancer patients, and compare to results generated from immortalized cell lines raised from primary oral cancer tissues, including oral squamous cell carcinoma line 4 (SCC4) and human squamous cell carcinoma line 3 (HSC3). Out of 4 human samples collected from male and female patients across various ages with variable risk factors, we observed an across the board reduction in RKIP expression. Two human samples demonstrated a significant increase in phosphorylated RKIP when normalized to total RKIP, however all 4 were increased when normalized to total cellular protein. The immortalized oral cancer cell culture HSC3 revealed significant increases in phosphorylated RKIP with no change in total RKIP expression, while line SCC4 demonstrated an increase in both total and phosphorylated RKIP. Results presented here indicate that oral cancers behave similarly to other cancers in terms of changes in RKIP expression and phosphorylation, although immortalized cell line expression profiles significantly differ from human tissue biopsies.

Extracellular vesicle-mediated phenotype switching in malignant and non-malignant colon cells

BACKGROUND

Extracellular vesicles (EVs) are secreted from many cells, carrying cargoes including proteins and nucleic acids. Research has shown that EVs play a role in a variety of biological processes including immunity, bone formation and recently they have been implicated in promotion of a metastatic phenotype.

METHODS

EVs were isolated from HCT116 colon cancer cells, 1459 non-malignant colon fibroblast cells, and tumor and normal colon tissue from a patient sample. Co-cultures were performed with 1459 cells and malignant vesicles, as well as HCT116 cells and non-malignant vesicles. Malignant phenotype was measured using soft agar colony formation assay. Co-cultures were also analyzed for protein levels using mass spectrometry. The importance of 14-3-3 zeta/delta in transfer of malignant phenotype was explored using siRNA. Additionally, luciferase reporter assay was used to measure the transcriptional activity of NF-κB.

RESULTS

This study demonstrates the ability of EVs derived from malignant colon cancer cell line and malignant patient tissue to induce the malignant phenotype in non-malignant colon cells. Similarly, EVs derived from non-malignant colon cell lines and normal patient tissue reversed the malignant phenotype of HCT116 cells. Cells expressing an EV-induced malignant phenotype showed increased transcriptional activity of NF-κB which was inhibited by the NF--κB inhibitor, BAY117082. We also demonstrate that knock down of 14-3-3 zeta/delta reduced anchorage-independent growth of HCT116 cells and 1459 cells co-cultured with HCT derived EVs.

CONCLUSIONS

Evidence of EV-mediated induction of malignant phenotype, and reversal of malignant phenotype, provides rational basis for further study of the role of EVs in tumorigenesis. Identification of 14-3-3 zeta/delta as up-regulated in malignancy suggests its potential as a putative drug target for the treatment of colorectal cancer.

RKIP-mediated chemo-immunosensitization of resistant cancer cells via disruption of the NF-κB/Snail/YY1/RKIP resistance-driver loop

Cancer remains one of the most dreadful diseases. Whereas most treatment regimens for various cancers have resulted in improved clinical responses and sometimes cures, unfortunately, subsets of cancer patients are either pretreatment resistant or develop resistance following therapy. These subsets of patients develop cross-resistance to unrelated therapeutics and usually succumb to death. Thus, delineating the underlying molecular mechanisms of resistance of various cancers and identifying molecular targets for intervention are the current main focus of research investigations. One approach to investigate cancer resistance has been to identify pathways that regulate resistance and develop means to disrupt these pathways in order to override resistance and sensitize the resistant cells to cell death. Hence, we have identified one pathway that is dysregulated in cancer, namely, the NF-κB/Snail/YY1/RKIP loop, that has been shown to regulate, in large part, tumor cell resistance to apoptosis by chemotherapeutic and immunotherapeutic cytotoxic drugs. The dysregulated resistant loop is manifested by the overexpression of NF-κB, Snail, and YY1 activities and the underexpression of RKIP. The induction of RKIP expression results in the downregulation of NF-κB, Snail, and YY1 and the sensitization of resistant cells to drug-induced apoptosis. These findings identified RKIP, in addition to its antiproliferative and metastatic suppressor functions, as an anti-resistance factor. This brief review describes the role of RKIP in the regulation of drug sensitivity via disruption of the NF-κB/Snail/ YY1/RKIP loop that regulates resistance in cancer cells.

STAT3 and sphingosine-1-phosphate in inflammation-associated colorectal cancer

Accumulated evidences have demonstrated that signal transducer and activator of transcription 3 (STAT3) is a critical link between inflammation and cancer. Multiple studies have indicated that persistent activation of STAT3 in epithelial/tumor cells in inflammation-associated colorectal cancer (CRC) is associated with sphingosine-1-phosphate (S1P) receptor signaling. In inflammatory response whereby interleukin (IL)-6 production is abundant, STAT3-mediated pathways were found to promote the activation of sphingosine kinases (SphK1 and SphK2) leading to the production of S1P. Reciprocally, S1P encourages the activation of STAT3 through a positive autocrine-loop signaling. The crosstalk between IL-6, STAT3 and sphingolipid regulated pathways may play an essential role in tumorigenesis and tumor progression in inflamed intestines. Therapeutics targeting both STAT3 and sphingolipid are therefore likely to contribute novel and more effective therapeutic strategies against inflammation-associated CRC.